Brief review of the theory of the muonic hydrogen Lamb shift and the proton radius

TL;DR

This paper reviews the theoretical understanding of the muonic hydrogen Lamb shift, emphasizing its role in precisely determining the proton radius and comparing it with previous measurements and theories.

Contribution

It provides a concise review of the effective field theory approach to the muonic hydrogen Lamb shift and discusses both QED and hadronic effects involved in the proton radius determination.

Findings

Muonic hydrogen Lamb shift measurement yields a proton radius significantly different from previous values.

Theoretical predictions incorporate both QED calculations and hadronic effects.

The discrepancy suggests potential new physics or the need for refined models.

Abstract

Recently the muonic hydrogen lamb shift has been measured with unprecedented accuracy, allowing for a precise determination of the proton radius. This determination is 5 sigma away from the previous CODATA value obtained from (mainly) the hydrogen lamb shift and the electron-proton scattering. Within an effective field theory formalism, I will define the proton radius and briefly review some aspects of the theoretical prediction for the muonic hydrogen lamb shift, studying both the pure QED-like computation and the hadronic effects.